NYC Used Whole Genome Sequencing to Solve Legionnaires Outbreak

New York City health officials used whole genome sequencing (WGS) and pulsed field gel electrophoresis (PFGE) to solve the Legionnaires Disease outbreak linked to the Opera House Hotel in the South Bronx. The outbreak, which sickened 128 people in the South Bronx killing 12 of them, was the city’s largest-ever.

Legionnaires’ Disease develops when water mist contaminated with Legionella bacteria is inhaled. It does not spread from person-to person. Symptoms include fever, cough, fatigue, confusion, aches and lung inflammation.

The source of contaminated water mist can be showers, faucets, whirlpools, swimming pools, fountains or cooling towers in air conditioning systems. City and state health officials worked together with investigators from the Centers for Disease Control and Prevention (CDC) to find the source of the the outbreak.

The sampled water from cooling towers in the South Bronx where the outbreak was concentrated. They used WGS, PFGE and sequenced based typing (SBT) to determine the genetic fingerprint of the bacteria in those sample and compared with the fingerprint of the strain that had sickened patients. The match wast the Opera House Hotel’s cooling tower.

“The city’s Public Health Laboratory worked closely with the State’s Wadsworth Center Laboratory and the Centers for Disease Control and Prevention to collect and process the samples from patients and cooling towers,” said Dr. Jennifer Rakeman, Assistant Commissioner and Director of the City’s Public Health Lab. “Legionella is notoriously difficult to grow on culture, which is why identifying a particular strain can sometimes take weeks. We brought together the best of the three laboratories and used multiple methods to determine the DNA fingerprints of cooling tower water and patient isolates, which enabled us to identify this strain and link patient isolates to the cooling tower isolates quickly.”